I have used my frozen milk twice for my 8 week old, most of it is stored in the Gerber bags, and when I thawed it with warm water and poured it into a bottle and noticed that even after swirling the milk several times, there are lots of little flakes. This milk is less than 2 months old. Is the milk still okay? I have fed it to my baby and he doesn't seem to mind it, but I am still concerned. Any advice?